Normal-danger-signal system.



L. A. HAWKINS & E. F. BLISS. NORMAL DANGER SIGNAL SYSTEM.

APPLICATION FILED APRA, 1910.

1,086,706. Patented Feb. 10, 191

WZINESSES: [NIZENZURE .ZIAURBJYE A. HAWKINS.

ILJIAE'H 1? 31.755:

QMI.

T351112 AT URNEY f "UNITED STATE rricn- 4 LAURENCE A. HAWKINS AND nLMnn r. BLISS, or scnnnncranr, new YORK, n's'srione, BY mnsnn ASSIGNMENTS, TO THE Union swrrcH arm SIGNAL commnr, 1

CORIOBATION OF PENNSYLVANIA.

NORMAL-DANGEB-SIGNAL SYSTEM.

Specification of Letters Patent.

Patented ea. acre.

To all whom it may concern:

Be it known that we, LAURENCE A. HAW- nms and Emma F. Buss, citizens of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Tmprovements in Normal-Danger-Signal Systems, of which the following is a specifi cation.

Our invention relates to block signal systerms in which the signals stand normally at danger and in which the signals are adapted to indicate danger, caution and clear, either by means or a three-position arm or by the equivalent arrangement of two two-position arms.

The object of our invention is to provide a simple circuit arrangement, for properly controlling the signals, involving a small number of line wires.

In a normal danger system of the type to which our invention relates, it is essential that when a train is in one block and two blocks ahead are clear, that the signal immediately in advance of the train should have been moved to the clear position, and the next signal in advance to the caution position. The train must thus control two signals in advance of it, and the signal two blocks ahead must control the clear position of the signal immediately in advance of the train. We accomplish this result by means of two line wires extending through each block in addition to the common wire. {One of these wires is the clearing wire which, when the train enters a block, clears or holds clear the signal next in advance, and the other is the control wire through which the clear position of a signal is controlled from the signal next in advance.

Our invention consists in arranging connections controlled by the track relay of a block for varying the resistance of the control circuit for that block and providing means responsive to the variation'resistance in that circuit for closing the clearing circuit of the block next in advance.

Our invention will best be understood by reference to the accompanying drawin which shows diagrammatically a norma danger signal system arranged in accordance with our invention.

In the drawing, A, A}, A and A represent the rails of four successive blocks.-

B, B and B represent track batteries.

QC represent track relays for thc-hloi ks winch form with the rails closed track circuits. Y Y I D are the signals, whi hmmtn stand at danger and which are adapted to indicate danger, caution and clear.

EEE representrela s controlled the track relays and contro ling the caution indications of the signals. v y

F l representrelays each controlled the s1gnal in advance and controlling the clear position placed.

G-G represent relays, which will he explained. I

H H represent resistances.

TT represent batteries for supplying current to the operating mechanisms of the signals.

J-J represent contacts which are shown in the conventional manner as operated by the signal mechanisms.

K represents the common wire.

L L represent the clearing wires and. l d-did represent what we have termed control wires.

The operation of the system is as fol.

h peace of and batteries of the signal at which it is lows :l-Vith a train occupying block A, as

is indicated in the drawing, the track relay 0 is .denergized. The relay E has its circuit open at the upper contact of track relay C so that current is cut ad from signal D. Re.- lays E and F gized so that this signal is in clear position. The circuit of relay E may be traced from the upper terminal of battery I throu h relay n. upper contact of track relay 6,

clearing wire L5 middle finger and back contact of track relay C and through common wire K hack to the battery. The circuit of relay F may be traced from the upper terminal of battery 1: through resistanceHfi relayG contact J control wire M lower finger and front contact of track relay Q relay F to common wire K and back to battery. The circuit which has just been traced includes contact J This contact is closed because signal D is in caution position, relay E being energized. The circuit of relay E may be traced from the upper terminal of battery I through relay Eff, upper contact of relay C clearing'wire L middle finger and front contact of relay '0,

at signal D are both enercontact of relay G wire L, middle finger has just been tracediincludes the contacts of -relay G This relay is energized through the following circuit :from upper terminal of battery 1 through resistance H relay G contact J control wire M, lower finger and back contact of relay C to common wire K and back-to battery.

It will be noted that the circuit which was traced for relay F passes through the winding of relay G This latter relay, however, is not energized since it is a relay of low resistance compared to relay F. For instance, the relative resistances of these two relays may be 16 and 1000 ohms res ectively, as is indicated on the drawing, so t at when the circuit is closed through the two relays in series, enough current flows to energize relay F but not suflicient to energize relay G Now, when the train advances from block A into block A the following changes take place: Relay C is denergized and opens the circuit of relay E which cuts ofi the battery from signal D and puts that signal at stop. Lower finger ofirelay C in passing from its front to its back, contact cuts relay F out of circuit and connects line wire M directly to common. This lowers the resistance of the circuit containing relay G and enough current now flows to energize this relay and causes it to close its contacts. This closing of its contacts connects clearing wire L through the middle finger and front contact of relay C and contact of relay G to clearing wire L which is connected through the middle finger and back contact of relay C to common. This energizes relay I) so that signal D is moved to caution. Contact J 3 is thereby closed connecting battery I through control wire M to relay F causing signal D to move to clear. position.

It will be noted from the above that the control wire M performs two functions first, when the train is in block A to connect relay F to contact J controlled by signal D and thereby place signal D under control of signal D Second, when the train enters block A, at which time signal D goes to stop position and relay F is no longer needed, this control wire M serves to energize relay G which, when energized, closes the clearing circuit L for the signal D Resistances H-I-I are placed in series a with the relays GG to limit the current drawn from the battery to the proper amount when the high. resistance relays F-F are cut out of circuit. With the relative resistances indicated for relays G and F, resistance H may be 100 or 150 ohms. Of course these values of resistances are merely illustrative and may be varied as desired.

Instead of cutting relays F, F, etc, out of circuit by open-circuiting them, they may,

a sence obviously, instead, be cut out of circuit by short circuitin This arrangementis shown for relay F w ich is simply short circuited by the lower finger and back contact of relay 0 when that relay is deenergized.

We do not desire to limit ourselves to the particular connections and arrangements of parts shown and described but aim, in the appended claims, to cover all modifications which are within the scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a normal danger signaling system, a plurality of closed track circuits including track relays, signals for the blocks adapted to indicate danger, caution and clear, two line circuits extending through each block, means included in one of said line circuits for controlling the caution indication of the signal for the block in advance and means connected with the second line circuit for controlling the clear indication of the block in accordance with said caution indication of said signal in advance, connections controlled by the track relay of each block for varying the resistance of said second line circuit, and means responsive to said varying of resistance for sending current through the line circuit of the block in advance which includes the means for controlling the caution indication of the signal in advance of said block in advance.

2. In a railway signaling system, a plurality of blocks, sources of current and track too ing it from the circuit of the auxiliary relay for the next succeeding block the auxiliary relay being responsive to the variation in the resistance of the circuit caused by such inclusion and exclusion, and connections controlled by each auxiliary relay when closed for closing the circuit of the means for controlling the caution indication of the next succeeding signal.

3. In a railway signaling system, a plurality of blocks, sources of current and track relays connected with the track rails of the blocks, signals for the blocks adapted to in-.

dicate clear, caution and danger; a caution indication relay and a clear indication relay for each signal, a circuit for each caution relay controlled by the track relay of the preceding block, an auxiliary relay for each block and a circuit therefor, contacts and connections controlled by each track relay for including the'clear indication relay of the corresponding block in and excluding it from the circuit of the auxiliary relay for the next succeeding block, the last mentioned circuit being proportioned so that the auxiliary relay is open or closed according to whether or not the clear. indication relay is included in the circuit, and a contact and connections controlled by each auxiliary relay for closing the circuit of the caution relay for the next succeeding block when the auxiliary relay is closed.

4. In a railway signaling system, a plurality of blocks, sources of current and track relays connected with the track rails of the blocks, signals for the blocks adapted to indicate clear, caution and danger; a caution indication relay and a clear indication relay for each signal, a circuit for each caution relay controlled by the track relays for the corresponding block and for the next .preceding block; an auxiliary relay for each signal and a circuit thereforv including a contact controlled by the corresponding signal, contacts controlled by each track relay for including the clearindication relay for the corresponding block in and excluding it from the circuit of the next succeeding auxiliary relay, the last-mentioned circuit being so proportioned that when closed the auxiliary relay is open or closed according to whether or not the clear indication relay is included in the circuit, and that the clear indication relay is closed when included in the circuit, and a contact and connections controlled by each auxiliary relay for connecting the caution indication relay for the next succeeding signal with the circuit of the caution indication relay for the corresponding signal.

In witness whereof, we have hereunto set our hands this first day of April, 1910.

LAURENCE A. HAWKINS. ELMER F. BLISS.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

